Dry rot outbreak caused by incorrect floor insulation.

The importance of ventilation and air movement in construction, is in my opinion greatly overlooked. A lack of ventilation and air circulation leads to mould, condensation dampness and of course creates ideal conditions for the germination of wood destroying fungi.
This timber survey yielded surprising results as it's not that common to find a Dry Rot out break in new construction. Modern design and building regulations are designed to eliminate moisture and the associated risks from buildings however, as this video highlights if during construction you deviate from the design, cut corners fail or fail to follow good practice even new construction will be at risk!
This is my 3rd significant dry rot survey in less than 6 weeks and we've currently 2 large dry rot projects ongoing! Dry rot is no mythical fungus, it is real!
Dryfix, There's a reason we're Yorkshire's Leading Damp and Timber Specialists!

[@roymichaeldeanable]

Everyone is building with an outer brick wall and an inner concrete block wall but filling the gap with 75mm 100mm insulation. Does no one realise that air vents above the DPC are all useless because the ventilation has been stifled I know nothing about building but obvious is obvious to me For many years there was an air gap, all around a double skinned house and in the roof space

[@dannymurphy1779]

You are meant to fit telescopic vents though.

[@normanboyes4983]

The air brick bridges the cavity and provides continuous ventilation from the outside block, through the cavity and through to the inner leaf (if there is a suspended wooden floor).

[@thesilvernetsurfer]

@@normanboyes4983 The cavity should be still air. Ventilation should be provided by telescopic air vents from outer wall to inner wall, below the insulation. Footings in the inner parts of the ground floor should be honeycombed brick/block work, or brick/block piers and timber beams, so as to allow air to flow under the floor insulation from the front to the back of the house. The result will be a wash of cold, dry air that desiccates the void under the insulation. This will prevent fungal growth, and insect infestation. To ensure this effort succeeds, all debris and dust should be scrupulously removed when the insulation is installed, and air bricks must be telescoped below the insulation level. Gaps in the insulation should be prevented by using breathable vapour barrier suspended between timbers and taped joins. Where the vapour barrier meets the walls, butyl rubber tape should be used to ensure there is no air leakage between the void space and the living space. That is the proper way to do the job. Services that penetrate the membrane to emerge above the floor line should have a neutral seal applied around the cables/pipes to maintain the vapour seal. A job worth doing is worth doing well or not at all. It must never be cheap to insulate a suspended timber floor properly: cheap means no attention given to the consequences of trapping moisture in the void...

[@normanboyes4983]

@@thesilvernetsurfer that’s what I said, with fewer words.

[@thesilvernetsurfer]

@@normanboyes4983 Sorry, meant to post as a comment so that those who do not know the textbook method could have it spelled out and beware of cheap quotes. As you probably are aware, cheap quotes on insulation jobs means there is a short it made to save the money. Insulation+shortcuts=disasters. Q.E.D No disparagement intended. I forgot to check what I was replying too before posting: dangerous!

[@georgeomalley6066]

Holy 💩,. That's Going to Cost a Bundle

[@gdr88]

That floor should have been hovered while the boards were up prior to installing the insulation.

[@gdr88]

loud and clear

[@neilmurphy3239]

RIP it up and start again every customer deserves a proper job

[@nicks4934]

Cut a recess in the kingspand by the airbrick. Simples

[@thesilvernetsurfer]

Nick S, then what about the resulting cold spot where the insulation isn't there? Cold spots are condensation buffets: all the mould you can eat...

[@tomvincent5596]

Wow that's mad

[@normanboyes4983]

Wow.😳

[@dannymurphy1779]

Job's a bad un!

[@linandy1]

There is no such thing as dry rot. Rot is caused by moisture loving mold that eats the wood. The dry dust left over is just that.

[@MadDog_Rules]

I would suggest you google dry rot and click on the images. Dry rot is caused by moisture and lack of ventilation. At 1.42 mark, you can clearly see the dry rot fungus.